Magnetic core



C. M. SUMMERS MAGNETIC CORE May 17, 1932.

Filed Nov. 9, 1931 lhvehtor:

Claude l LSummers His Attorhe Patented May 17,

UNITED CLAUDE M. SUMMERS, 915' FORT "iR-"AYNEINDIANA, ASSIGNOR TOGENERAL ELECTRIC GOMPANY, A. CORPORATION 035 NEW YORK MAGNETIC COREApplication filed November 9, 1931. Serial No. 53'3/792.

My invention relates to electrical induc tion apparatus such as reactorsand transformers, and more directly to magnetic cores for suchapparatus. The electrical character- 5 istics of such apparatus mustoften be within very narrow limits or the apparatus may not operatesatisfactorily in the circuits in which they are intended to be used.The characteristics of some such circuits also vary 1 because ofmanufacturing limitations although the circuits may be intended to be.alike. For instance, it is not practically pos-' sible to produceelectrical condensers in quantity without variations of several per centin the capacities of the different units.

Reactors which are to be used with such condensers in some circuits musthave correspondingly different characteristics. The general object ofthe invention is to provide reactors, transformers and the like with animproved magnetic core constructed to permit convenient adjustment ofthe magnetic and electrical characteristics of the cores and theirwindings.

The invention will be better understood from the following descriptiontaken in connection with the accompanying drawings in which Fig. 1 showsa reactor constructed in accordance with the invention, and Figs. 2, 3and 4 are views of parts of the magnetic core of the reactor shown inFig. 1.

Like reference characters indicate similar parts in the difi'erentfigures of the drawings.

The reactor. shown in Fig. '1 of the drawings includes a magnetic core10 having a winding leg 11 surrounded-by a winding 12. Two outer legs 13and 14 are connected to the ends of the winding leg 11 by yokes 15 and16 to provide return magnetic paths for the magnetic flux in the windingleg. The core 1.0 is built up of magnetic laminations 17, eachlamination being formed in two sections with the joints in the differentlaminations offset or staggered as shown in Figs. 2 and 4.

In order to permit the electrical characteristics of the reactor to beadjusted, one or more partial air gaps 18 are formed in the magneticcircuit of the core, two such gaps being shown in the drawings. Each ofthe non-magnetic gaps 18 is formed nearan end of the winding leg 11 sothat it is readily accessible after thewinding 12 has been assembled inposition on the core. Each gap extends entirely through the core butonly part way across the winding leg 11 so that the winding leg isconnected integrally at both ends with the core yokes 15 and 16.

The presence of the non-magnetic gaps 18 in the magnetic circuit of thecore increases the magnetic reluctance of the core and'thus affects theelectrical characteristics of the reactor. If a test of the reactorshows that it does not have the desired characteristics because of toohigh reluctance of the core, one or more magnetic inserts 19 are fittedinto one or both of the gaps 18, the proper number of inserts being usedto reduce the reluctance of the core to a value corresponding to thedesired characteristics of the core. The inserts 19 are small, thin,magnetic sheets which may be cut or punched from larger stock sheets ofthe desired thickness. The width of each insert is preferably equal tothe width of each gap 18 .or a little less and the length of each insertis preferably equal to the thickness of the core 10. When the inserts 19are in place in the gaps, they are at right angles to the direction ofthe core flux and their efi'ect is to shorten the gaps and thus reducethe reluctance of the core. The inserts may be secured in place in thegaps by small pieces of any suitable nonmagnetic material such as paperforced into the gaps with the inserts. The inserts 19 may be removed anda diiferent number of them placed in the gaps 18 if a change in thecharacteristics of the reactor is desired at any time.

The invention has been explained by describing and illustrating aparticular form and application thereof, but it will be apparent thatchanges may be made without departing from the spirit of the inventionand the scope of the appended claims.

lVhat I claim as new and desire to secure by Letters Patent of theUnited States is:.

1. Electrical induction apparatus including a magnetic core having a gapextending "partially across the magnetic circuitof the core, the coreextendingintegrally past at least one side of said gap, and a magneticinsert secured in said gap to reduce the magnetic reluctance of thecore.

2. Electrical induction apparatus includ- 5 ing a magnetic core having agap extending partially across the magnetic circuit of the ,core, thecore extending integrally past at least one side of said gap, and a thinmagnetic sheet insert secured in said gap at a right angle to thedirection or" the core flux to reduce the magnetic reluctance of thecore 8, Electrical induction apparatus includ ing a magnetic core havinga Winding leg, a Winding surrounding said Winding leg,

said winding leg having a gap near one en thereof and extendingpartially across the leg, the leg extending integrally past at least oneside of said gap, and a magnetic insert secured in said gap to reducethe magnetic reluctance of the core.

&. Electrical induction apparatus including a magnetic core having atleast one gap extending partially across the magnetic circuit of thecore, the core extending integral- 2 ly past at least one side of eachgap, and magnetic sheet material secured in each gap to reduce themagnetic reluctance of the core to a value corresponding to desiredapparatus characteristics. 4

5C In witness whereof, I have hereunto set my hand.

CLAUDE M. SUMMERS.

